Title: Fatal error: Call to undefined function apc_fetch
Last modified: August 20, 2016

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# Fatal error: Call to undefined function apc_fetch

 *  Resolved [crashnet](https://wordpress.org/support/users/crashnet/)
 * (@crashnet)
 * [13 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-apc_fetch/)
 * `Fatal error: Call to undefined function apc_fetch() in /wp-content/plugins/w3-
   total-cache/lib/W3/Cache/Apc.php on line 158`
 * Brought down wordpress after the last upgrade was installed. Some other W3TC 
   enabled sites on the same server running same config (but different plugins and
   themes) did not break.
 * [http://wordpress.org/extend/plugins/w3-total-cache/](http://wordpress.org/extend/plugins/w3-total-cache/)

Viewing 6 replies - 1 through 6 (of 6 total)

 *  Plugin Contributor [Frederick Townes](https://wordpress.org/support/users/fredericktownes/)
 * (@fredericktownes)
 * [13 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-apc_fetch/#post-3437576)
 * To manually change engine you can edit the wp-content/w3tc-config/master.php 
   file and change pgcache/dbcache/objectcache.engine => ‘apc’ to ‘disc’ where applicapble.
 *  Thread Starter [crashnet](https://wordpress.org/support/users/crashnet/)
 * (@crashnet)
 * [13 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-apc_fetch/#post-3437622)
 * That did not work. After I changed all 3 to disc I get a 500 and it doesn’t even
   get logged to the vhost or apache’s global error log.
 *  Thread Starter [crashnet](https://wordpress.org/support/users/crashnet/)
 * (@crashnet)
 * [13 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-apc_fetch/#post-3437623)
 * Also, eventhough I never before used APC caching, apc.ini is set to load but 
   apc remains off.
 * PS: I have newrelic installed.
 *  Plugin Contributor [Frederick Townes](https://wordpress.org/support/users/fredericktownes/)
 * (@fredericktownes)
 * [13 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-apc_fetch/#post-3437638)
 * Remove the config files in wp-content/w3tc-config/ and wp-content/cache/config,
   then try again. The plugin does not use APC by default so it must be set elsewhere.
 * I could be a config value from your old config in wp-content so if you have no
   issue resetting settings you can rename the old config file for testing purposes.
   Its called w3-total-cache-config.php.
 *  Thread Starter [crashnet](https://wordpress.org/support/users/crashnet/)
 * (@crashnet)
 * [13 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-apc_fetch/#post-3437644)
 * I replaced every instance of ‘apc’ for ‘disc’ in all those config files and the
   plugin started working. I then upgraded to 0.9.2.7 and this time the upgrade 
   didnt break anything.
 * I am not sure why 0.9.2.6 decided to switch all caches to ‘apc’
 * thanks
 *  [Purab](https://wordpress.org/support/users/purab/)
 * (@purab)
 * [12 years, 8 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-apc_fetch/#post-3437799)
 * I faced similier issue. I just deleted the w3 cache then removed the cache directory
   from wp-content folder and reinstalled the w3 cahce plugin and configured again..
   That works for me perfectly.

Viewing 6 replies - 1 through 6 (of 6 total)

The topic ‘Fatal error: Call to undefined function apc_fetch’ is closed to new replies.

 * ![](https://ps.w.org/w3-total-cache/assets/icon-256x256.png?rev=1041806)
 * [W3 Total Cache](https://wordpress.org/plugins/w3-total-cache/)
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## Tags

 * [W3TC](https://wordpress.org/support/topic-tag/w3tc/)

 * 6 replies
 * 3 participants
 * Last reply from: [Purab](https://wordpress.org/support/users/purab/)
 * Last activity: [12 years, 8 months ago](https://wordpress.org/support/topic/fatal-error-call-to-undefined-function-apc_fetch/#post-3437799)
 * Status: resolved